Subject: Re: DHCP and static configuration

From: James Kempf <[email-masked]>
Date: Mon, 13 Sep 1999 12:38:50 -0700 (PDT)

>With respect, Windows 98 and Windows 2000 do IPv4 stateless
>autoconfiguration, in the absence of a DHCP server.  And since
>these platforms constitute the bulk of the clients for service
>location, I would like to be able to drop a printer (or other
>device) onto the network, and have it "just work".
>
>

I believe the ZEROCONFIG working group intends to start with
the Windows stateless IP address configuration method,
since I think it is also being used by Apple as well.

>> Are you saying you want a UA on the printer?
>> I suppose if you need to find an LDAP server to
>> determine configuration, that would work OK. Why not
>> simply put the SLP scope into the LDAP attributes if
>> you don't want to use DHCP?
>
>Does this count as static configuration?  If so, then I
>have much less of a problem with the SA static configuration
>requirement, since this would render it much less onerous.
>
>

It is not standardized so it won't be interoperable, but much in
the area of LDAP schema is currently not standardized.

Another alternative would be to simply use HTTP instead of 
LDAP, and have a web page on the net that contained configuration
information. This would have the advantage that it could be
a lot lighter weight. And HTTP is currently somewhat more
widely available.

		jak

---

From: Terry Lambert <[email-masked]>
Date: Mon, 13 Sep 1999 12:58:18 -0700

> since I think it is also being used by Apple as well.

It's also what's documented in the draft, and the IP
address range for "link-local" is already registered to
IANA.

I really think that we need to flesh out how SAs can operate
in the "DEFAULT" scope; the demands for either DHCP or static
configuration data are, IMO, too strict, and make too many
assumptions about enterprise level infrastructure being
available to SAs in all environments where they are expected
to be deployed.

I tend to harp on the printer example.  That's because it's
a good example.  It's the most likely think you are going to
plug in after you plug two computers into a shared hub.  It's
also the level at which this stuff needs to work for what
appears to be the majority of installations.  There are at
least ten thousand small businesses for every I.B.M. or Sun.

> It is not standardized so it won't be interoperable,
> but much in the area of LDAP schema is currently not
> standardized.

It's relatively trivial to translate any MIB into an
LDAP schema, so in as much as MIBs are standardized,
there exists standardized schema which can be used with
LDAP.

One big issue here, and one which is apparently ignored in
the SLP printer URL definitions I've seen so far, is that
there really hasn't been a lot of vendor interoperability
work done.  As with SNMP MIBs, the use of vendor defined
per device schema is one of the bad things Which Must Die.

> Another alternative would be to simply use HTTP instead
> of LDAP, and have a web page on the net that contained
> configuration information.

Down this road lies vendor defined per device schema for
XML.  It's a bad place to go.

> This would have the advantage that it could be a lot
> lighter weight. And HTTP is currently somewhat more
> widely available.

Again, I think this is attempting to wedge something into
existing enterprise infrastructure, at the expense of doing
the right thing, and defining standards which mandate that
different vendors configuration practices be interoperable.
I'm _really_ against making decisions that benefit the
existing installed base, at the expense of achieving the
intended goals.

HTML is frequently abused as a tunnel for all sorts of
inappropriate data transfers these days, and laying more
burden on it as if it were a generic transport is wrong.

I would be much more likely to accept an answer like "ACAP",
with all of the flaws inherent in that design, than to try
and wedge yet another proprietary text format in HTML.  8-(.

I think the right answer is a common replicated information
protocol of some kind, that can be intermediated by subschema
definitions concerning the data that does (and doesn't) get
replicated.  I've actually been working on one for a while
now.  But this is getting somewhat off-topic for this working
group, so I'll stop talking.  8-).

-- Terry Lambert
-- Whistle Communications, Inc., an I.B.M. Company
-- [email-masked]
-------------------------------------------------------------------
This is formal notice under California Assembly Bill 1629, enacted
9/26/98 that any UCE sent to my email address will be billed $50
per incident to the legally allowed maximum of $25,000.